Seal for electric discharge devices



7 Sept. 29, 1936.' A. AMILLAC SEAL FOR ELECTRIC DISCHARGE DEVICES FiledJuly 31, 1930 invencov 1 QUQQT'E 'n'w'iiiac,

His Attovngg.

Patented Sept. 29, 1936 UNITED STATES SEAL FOR ELECTRIC DISCHARGEDEVICES Albert Amillac, Belfort, France, assignor to General ElectricCompany, a corporation of New York Application July 31, 1930, Serial No.472,008

r In France September 4, 1929 8 Claims.

My invention relates to means for producing a gas-tight seal between thewalls and electrode leads of an electric discharge device, such as avapor rectifier or the like, and has for its principal object theprovision of an improved seal which can be relied upon to prevent theleakage of airinto the evacuated vessel of the device, to support theelectrodes and to insulate the electrode leads from the wall of theevacuated vessel.

In the construction of large vapor electric rectifiers, great difficultyin producing a gastight seal between the electrode leads and vesselwalls has been heretofore encountered. It has been attempted tointerpose a body of fused basalt or like vitreous material between thevessel wall and electrode lead for the purpose of supporting theelectrode and producing a hermetical seal between the vitreous materialand the lead. As a result of such attempts, it has been foundimpractical to join the vitreous insulating body directly to the leadbecause of oxidation of the lead during the attachment of the vitreousmaterial to the lead, this oxidation tending to produce fragility andporosity at the juncture between the vitreous material and metal.

In accordance with my invention, this difliculty is obviated by theprovision of a layer of reducing or neutral material such as copper,nickel, varnish, lacquer or the like, at the juncture between thevitreous material and metal and by so rearranging the various parts ofthe seal that the juncture between the metal and vitreous material isnot subjected to the rapid temperature changes heretofore encountered.As a further precaution against leaks, this juncture is provided at itsouter edge with an additional seal including mercury or other suitablesealing material.

My invention will be better understood from the following descriptionwhen considered in connection with the accompanying drawing, and itsscope will be pointed out in the appended claims.

The drawing is a sectional view of an insulation seal wherein myinvention has been embodied.

For the sake of simplicity, it is assumed that the insulating substanceis fused basalt but it goes without saying that this body could be ofany suitable vitreous material. The joint, the tightness of which is tobe insured, is that between the metal member I and the insulator 2. Theline along which the surface of this joint protrudes from the apparatusis covered with an annular joint 3 of plastic material, on which restsrigid metal element 4 which is likewise ringshaped and which is properlyclamped on the plastic joint 3 by means of screws 5, throughintermediate elastic washers 6. The reaction of the pressure exerted byscrews 5 rests, through the intermediate ring 9, on two semi-rings Iwhich fit in a groove 8 that is provided in part I. Ring 9 is alsoequipped with stop pins ID, with nuts and elastic washers, which press a10 cover II on cylinder I2, below which a plastic joint I3, similar tojoint 3, is located, which joint is properly squeezed against the uppersurface of the basalt insulator 2.

In this manner an annular chamber is obl5 tained which is limited asfollows: Part i, upper surface of insulator 2, cylinder I2, and finallycover II. In this annular chamber a certain quantity of mercury I4 isintroduced which covers entirely the plastic joint 3. There is pro- 20vided in this manner a joint which in itself is quite hermetical andwhich answers the purpose even if the contact surface between part I andthe basalt insulator becomes permeable to air or mercury.

A float I5, which is visible from the outside and which comprises agraduation, permits of controlling the mercury level which covers thejoint.

The improved arrangement also has the purpose of reducing the heattransmission through conduction between the anode-carrier rod It onwhich anode I1 is screwed, and insulator 2, in order to lower thetemperature of this insulator and to reduce the speed at which it heatsup.

To this end, the rod I6 does not rest directly on insulator 2, but on anintermediate metallic sleeve I, which is introduced between the anodecarrier rod I6 and the basalt. Besides, the weld I8, through which rodI6 and sleeve I are made 40 integral with each other, is well above theupper level of insulator 2. Finally, space I9, which is connected withthe vacuum system, is provided between the anode-carrier rod and sleeveI. Through this arrangement, the temperature drop 45 between the anode I1, which constitutes the heat source of the system, and the top of theinsulator 2, which is in contact with sleeve I, is duly increased.

What I claim as new and desire to secure by 50 Letters Patent of theUnited States is:

1. In a seal for electric discharge devices, the combination of a metalsleeve provided at one of its ends with a non-oxidizing coating, anelectrode lead attached to the other end of said 55 sleeve and spacedfrom said sleeve throughout the remainder of its length, a body ofvitreous material joined to said sleeve through said nonoxidizingcoating to form a seal for said lead, and

additional sealing means for said lead including its ends with anon-oxidizing coating, an electrode lead attached to the other end ofsaid sleeve and spaced from said sleeve throughout theremainder of itslength, a body of vitreous material joined to said sleeve through saidnon-oxidizing coating to form a seal for said lead, and additionalsealing means for said lead including a mernber of plastic material incontact with the jointure of said body and sleeve and a body of mercurycover ing entirely said member of plastic material.

. In a seal for an electrode of an electric dis: charge device, a bodyof vitreous material, means including a metallic member to join saidelectrode to said body, a sealing member of plastic material, and meansto press said sealing member against said body and said metallic memberat the jointure of said body and said metallic member.

4. In a seal for electric discharge devices, the combination of a metalsleeve, an electrode lead attached to one end of said sleeve, a body ofvitreous material joined to said sleeve at the other end thereof, anannular member of plastic material, and means to maintain said member incontact with said body and said sleeve at the jointure said body andsleeve' 5 Ina seal for electric discharge devices, the combination of aninsulation member, an anode,

lead and a metal sleeve joined at one of its ends to said lead and atthe other of its ends to said member, and additional sealing meansincluding an annular member of plastic material supere posed on thejuncture between said member and said sleeve, means comprising acylindrical member to press tightly said annular member against saidjointure, a second annular member of plastic material surrounding saidfirst-named annular member, means comprising a cylindrical member,separate from said first-named cylindrie cal member to press tightlysaid second-named annular memberagainst said insulating member toform anannular chamber between said second-' cylindrical member and saidsleeve, and.

a body of mercury in said annular chamber covering said first-namedannularmember and in contact with. said second-named annularmember. I v6. In a seal for electricdischarge devices, the combination of a body ofvitreous material, an anode lead, a metal sleeve attached at one of itsends to said lead and. joined at the other of its ends to said body atone end of said body, and

additional sealing means for said leaduincluding f devices, thecombination of a metal sleeve provided at one of a member of plasticmaterial in contact with the jointure of said body and sleeve, meanscomprising a cylindrical member to press tightly said annular memberagainst said jointure, a second annular member of plastic materialsurrounding said first-named annular m'ember, means comprising acylindrical member separate from said first-named cylindrical member topress tightly said second-named annular member against said insulatingmember to form an annular chamber between said second-named cylindricalmember and said sleeve-and a body of mercury in said annular chambercovering said first-named annular'mernber and in contact with saidsecondnamed annular member.

7. In a seal for electric discharge devices, the combination ;of a metalsleeve,. an electrode lead attached to one end'of said sleeve, a body ofvitreous material joined to said sleeve at the other end of said sleeve,and additional sealing means for saidlead including a member of plasticmaterial in' contact with the jointure of said body and sleeve, meanscomprising a cylindrical member to press tightly said annular memberagainst said jointure, a second annular member of plastic materialsurrounding said first-named annular member, means comprising acylindrical member separate from said f rst-named cylindrical member topress tightly said second-named annular member against said insulatingmember to form an annular chamberbetween said second-named cylindricalmember and said sleeve, and a body of in said annular chamber coveringsaid. first-named annular member and in contact withsaidsecend-narnedannular member.

8. Ina seal for electric discharge devices, thecombination f a metalsleeve, an electrode lead attached to one end of said sleeve and spacedradially therefrom throughout ,the remainder of the length of saidsleeve, a body of vitreous mate rial joined to said sleeve at th e otherend of said sleeve, the portion of said sleeve extending from the jointbetween said body and said sleeve to that pqrtion-of thesleeve to whichthe electrode lead ,is. attached being of substantiallength toincreasethe temperature drop between said electrode, andsaid body, andadditional sealing means for s aidlead including a member of plasticmate? rial in contact with the jointure of said body'and' sleeve, meanscomprisingacylindrical member to press tightly said annulargmember;against said jointure, a secondannular member of plastic materialsurreunding-said first-named annular member, vmeanscomprising avcylindrical mem: ber separate from said first-named cylindrical memberto press tightly saidsecond-named, annularmember against said insulatingmember to form an annular chamber'between said second: named cylindricalmember and said sleeve, and a body-oimerenry inesaid-annular: chambercovering saidfirstenained-annular member and in con tact with saidsecond-namedannular member.

ALBERT AMILLAC;

